I enjoy that you cover not well know accidents. It seems like everytme I watch a mentour video it's about an accident that has already been covered by air crash investigation / mayday or other major documentaries. It isn't as interesting or fun to hear about accidents I already know about. Thanks
I feel mean saying it cos Mentour is obviously a nice guy and a professional - deeply invested in the notion of learning from history to improve safety and educating a wider audience on those issues. At the same, I sometimes find the level of detail he incorporates makes me wilt a bit. Also while I am the first to abhor blame culture where people operating within it become afraid to own up to mistakes for fear of sanction, I do feel that that has to be balanced with recognition of the degree of culpability of each and every party that was in some way involved with an incident. There have been times where - unlike our delightful host on this channel who generally prefers to ask us what we think rather than pronouncing on it himself - Mentour is happy to indicate a preference for any other possibility than pilot ineptitude, laziness, ill preparedness etc, commonly euphemistically referred to as pilot error which in fairness I think also includes less proscriptive failures. Naturally, there are some aspects of flight which can be influenced by very human qualities which make it a grey area as to whether they excuse, or otherwise, poor performance. In Green Dot, I recently endured a fair amount of criticism for daring to suggest that two Air France pilots, while flying from New York to Paris, on the approach to their destination inadvertently input opposing commands into their respective yokes, should face consequences, albeit I did not even obliquely imply they should be hung, drawn and quartered, or even lose their jobs. Incidentally, their comically poor management caused sufficient confusion and loss of control to bring the aircraft as near to crashing as it's possible to do, without actually crashing. Everyone else dismissed that option as, since the flight was a "graveyard shift" (which no American airline operated for that reason) the pilots were "fatigued" and therefore blameless. Similarly, Mentour felt that the pilot in command of TransAsia Airways Flight 235, who instead of switching off the malfunctioning engine in response to it flaming out on take-off, shut down the one which was still working. You can easily find the result of his actions all over the 'net, with dramatic and horrifying footage of the plane, banked at 90 degrees as it flies over a viaduct, its left wing tip first hitting a car travelling on it and then the guardrail, before disappearing out of shot although we are all to aware of the tragic outcome. Mentour ascribed most of the blame to the airline for failing to provide adequate competence checks and training which I disputed since Transasia could show that he had recently been tested which was failed so was given further instruction resultig in a pass of the retest. Well excuse me, I really don't think any more could have been done by the airline and that this was just individual incompetence. As said at the beginning, I don't like blame culture but denial of responsibility is just as bad - which you don't get here and, along with the more succinct and pithy script and engaging delivery by Mini Aircrash Investigation's creator - that is why I much prefer his channel to any others!
Mentour provides a professional pilots insight into the accident that other shows may not have. His production value is also very good. In short, both channels do what they do very well
You are becoming one of my favourite aviation channels due to the fact that you cover much lesser known events being a TH-camr myself means I don’t get much time to watch others content so I truly appreciate your efforts!
As an ATC something you may not know is giving takeoff clearance we use cleared FOR takeoff and landing it’s cleared TO land. You won’t ever hear cleared to takeoff or cleared for landing. Really enjoy your videos!! It’s definitely going to be an operational error on the ATC. We are human like everyone else but we hold ourselves in a higher regard.
Is it too Naive to believe that "Transponders" could be used to Identify Aircraft on those Runways and Taxiways so that ATC can see their Actual positions on the Screen? Or does this happen? Huge admiration for you guys at ATC - such responsibility!! When talk about "extra runways" are ATC Personell ever consulted?
Whenever automation lies about its current state, because of a design decision, it is a bad design decision. Really interesting and frightening video. 👍
Yep, there's no point saying I'm at x, when I'm really at y. The makers of those design decisions need someone to have a word. I hope that that system has been changed now where the state given is the actual state.
The rationale was good though. The "in-air" flag is supposed to mean "if I'm not in-air, you can ignore me for the purpose of TACAS advisories and ATC conflict advisories, I'm taxiing or parked". For that purpose a plane in takeoff phase *is* "in-air" and it's reasonable to broadcast as such. Doing so could allow TACAS to warn a plane that's doing a go-around that someone else is about to take off into their path, for example. The problem is that the flag must've been poorly specified. So the ground runway incursion system assumed it could use the in-air flag to ignore aircraft. But in reality the in-air flag was the "not definitely still on the ground" flag. In-air = false meant "definitely on ground" but in-air = true did NOT mean "definitely in air not on ground". Not enough attention was paid to the boundary conditions. And it's clear the runway incursion system wasn't tested adequate either. Because this should've come up in testing with high speed taxi, or with one aircraft about to land on an occupied runway.
People are misunderstanding these systems - they aren’t really designed for this scenario in the first place, and are NOT used for general ATC operations on a normal basis; they’re something in the background that’s “there” and the normal procedures and safety margins are what keeps aircraft safe on a normal basis. Most of the ground monitoring equipment is used for inclement weather, fog, etc. For example, if one aircraft had been back-taxiing while another entered the active runway, the system would have worked perfectly fine, THAT is what it was designed for.
they should RAAS andthe CGYAS be replaced by ATSD, with planes also having theirown ground radar, upgrade RAAS with a warning, " AIRCRAFT STILL ON RUNWAY, ABORTABORT> i mean automation isnt bad at al As long it is implemented correctly and done good.
My thought process: "Ah, ATC error. No, wait, _pilot_ error. Uhm.. no, system design error!" In conclusion, systems could be better designed, ATC could've kept better track of the planes... But I still think the biggest fault lies on the pilot (or whoever took care of the radio) to not follow up when they got no read-back. Colliding radio calls seem to be common, they shouldn't have let that go, especially in a situation like this. (Maybe they were about to? After all, everything happened quite fast.)
I'm no airline pilot but I would think if you would hesitate for any clearance you're not sure about, it would definitely be a takeoff clearance. Seems complacency kicked in a little bit.
Maybe Im being naive here, but I thought, no ATC was supposed to clear another plane to land or for takeoff for a runway, until they had confirmation, the runway is clear. I mean, he just assumed, the first plane had taken off. He didnt get radio confirmation, he didnt get up and check visually, nothing. He just assumed. But apparently I also assumed wrong. Already a nervous flyer, this doesnt really make me feel better about it.
I agree. Systems did what they were programmed to do, which left the chance for just this eventuality. My time in the navy taught me no message is received unless properly acknowledged. They pilot entered an abnormal situation by rejecting the takeoff, so it should have been very important to verify his status report had been received.
Thank you for documenting these stories. Often the media forgets these events, just before no fatalities occurred. However, these stories are really important to aviation safety and for anyone who loves this industry. Great video. Your channel is awesome!. Looking forward to your next video.
Agreed. Should have made that well known, in hindsight. Except, he made the call, and you don't always get acknowledgement. Just good fortune that the 777 pilots had 20/20 vision. Nobody was at fault in my opinion, everybody did what was expected of them, just bad circumstance lead to a potential disaster that didn't come to fruition, thankfully.
I noticed the similarities between this incident and Tenerife. I really like your knowledge and articulate way of narrating your videos. Thanks Mini man 😘
First point is that the number of things that went wrong here is truly impressive and by default makes it hard to pin causes(not blame) anywhere. Here are my two thoughts. 1) The 777 needed to visually verify the other aircraft as airborne. If I can spot a 150 5,000 feet down the runway when I'm setting up for my roll, then a small jet can very easily be seen. 2) Though the pilots of the smaller jet where terribly busy, there is a "stepped on" audio que that all pilots should be familiar with. It's not like it's a terribly uncommon occurrence. A reception of the abort call out until after the step on que stopped might have assisted. Again, these are just two thoughts on contribution, not blame. It's easily understood that these are two small things often overlooked every day and the pilots where in a super high workload of flight.
Two very good points. A 90 seat regional jet may be small compared to a 777, but hardly "tiny" as described in the video. It's about the size of a DC9. The pilots in the 777 should have had no problem seeing that it hadn't taken off.
This comment makes absolutely no sense whatsoever. It’s not even proper English. It sounds like the person writing it might be a pilot himself, but I find it hard to believe a person with such poor language skills could achieve a pilot’s license.
1. No it doesn't - that is the controller's job and he must not issue take-off clearance to the B777 until it is confirmed. 2. The garbled transmission communicating the abort is simply communication - it is not structural to the ATC safety net. It the controller said "Cleared take-off" to the B777 it is his error - he had not confirmed the runway was safe to use before doing so.
@@johnbolwell5969 And here we get why I listed these as thoughts, not as definitive reasons or as causes. In close insidents it's important to look at the issue from all available perspectives and see what could have changed the outcome. There is a concept on aviation that can be boiled down to "maximum available safety." When vfr is present and an ifr aircraft is in that zone it is desired for that aircraft to maintain what they can of their own VFR traffic scan. If you listen to ATC recordings or fly through tml or arr/dep airspace you'll likely hear a transmission like this: Ifr callsign, traffic at your three, 500 below, a vfr contact. They're looking for you. Tml, callsign, afirm *looking for traffic* Now they are ifr. Spacing and separation is no longer their responsibility. But because the safety conditions allow it, the ifr will also perform visual safety procedures. Had this happened on the ground the incident would have amounted to a simple call of "negative, traffic on runway." Do I blame the 777 pilots. Of course not. Strictly speaking they where following clearance that should have given them traffic avoidance. They where in a stupidly high workload faze of flight. However could the situation have been a avoided like this. Yes. Thus it serves as a valuable reminder for pilots to stay vigilant to the maximum degree available and possible. It serves as valuable advise that helps fight complacency.
@@Fkruus Sure, I get that. The visual scan of all traffic is good practice and, as in this case, made the difference - we'd call that "belt & braces" but if we are talking about where formal responsibility lies, for IFR traffic it is firmly vested in the ATC system. Safety should not occur by accident; it should be the natural result of proper application of ATC procedures. You wouldn't hear that call in the London Terminal area - VFR not allowed. At Heathrow we do give traffic calls to IFR when we do multiple arrival streams but it's not the norm - the r/t loading is already saturated.
The problem here is the use of systems for multiple functions they weren't designed for. And if a system is designed to do two completely different things there are also problems sometimes when those two parameters overlap or come into contact. There is a compromise occuring that gives precedent to avoiding collisions immediately after taking off instead of on the ground. And any other system dependent on a flawed system is also flawed.
The chief issue here is that the E190 pilots did not get a tower confirmation that they were rejecting take-off. If the tower heard them, the pilots would have received acknowledgement from the tower...
I'd like to actually hear that transition of calls because there could have been a lot of radio chatter where the E190 couldn't repeat the call. The 777 should have been able to confirm that there were no aircraft on the runway prior to getting over 100 knots though. You can always use your eyes, you can't always use the radio.
I was watching the news a few weeks back and they mentioned this. However, it was in the break room at work, so I couldn't really hear the details due to other sounds in the room. Thank you for telling the story :).
The so called "Take off clearance" mentioned at time 6:05 in this video is actually called a "departure clearance". The words "take off" are only used in connection with the actual clearance to start accelerating and taking off. Pilots who have only received their departure clearance will always hold their position on the runway until they receive a take off clearance containing the magic words "take off". In this case however, after receiving their departure clearance, they accidentally also received a take off clearance
My son is a federal air traffic control supervisor and I fly fairly often. I have a deep appreciation for how complex their jobs are, and I marvel at their abilities to juggle everything in their heads while they talk to multiple aircraft. I believe the causes of this near miss are the smaller jet not confirming their report to the tower of the rejected takeoff when the tower didn’t acknowledge it; a poor system design that allows one communication on the same frequency to cancel out another (a major contributor to the Tenerife accident), perhaps the controller getting in the routine of not confirming that a plane took off; and a tower design that doesn’t allow the controller to see the runways easily. The last was a major cause of that LAX runway collision in 1991- the controller’s view of the runway was obscured by the tower design. Great channel!
6:08 i thought that would be a departure clearance. From what i learned the word takeoff should never be used, except for the actual takeoff clearance permitting to start the takeoff roll
I agree, I've never heard of an ifr clearance referred to as a takeoff clearance. Not to mention major airports have a dedicated clearance delivery freq for this and it occurs before the plane even taxis out. The tower might have some slight amendment to the departure routing/ assigned altitude but that would normally be issued in conjunction with the actual takeoff clearance.
@@unpopularopinion8608 yeah, thats what i understood as well. What i hear quite frequently when it comes to amended departure clearances or "when airborne" instructions is like "Delta 1234, fly heading 320, runway 28 cleared for takeoff", but it could also be issued as "Delta 1234, on departure, fly heading 320, runway 28 line up and wait". Never uses the word takeoff though.
This is right. A take off clearance is the words “cleared for take off” and it tells a pilot they are able to take off. I think the wording of the video is just wrong. “Departure clearances” are part of the standard IFR clearance “cleared Sydney via DOSEL planned route DOSEL1 departure” etc.
6:07 If I'm not mistaken, the takeoff clearance is "[callsign] cleared for takeoff" the clearance of how to fly from 1 airport is called the departure clearance According to mentour pilot's video, he did say "A-C-A606 cleared to enter runway 06L and cleared for takeoff"
Control towers were designed at the early ages of commercial fligt to overlook all takeoffs and landings. For some reason, nowadays, Tower ATC are more focused on planning rather than lookin through the window.
Pilot of the 190 did not hear the controller acknowledge his rejected takeoff... because the controller never heard it. Everyone reads back everyone else's transmissions to assure they're communicating. What's the smaller risk -- that the jet will crash because a bird fouls one engine at takeoff or that jets will collide because one pilot rejects a takeoff and fails to communicate it to the tower? Fails to communicate is the correct terminology because the rejecting pilot dropped the ball when he didn't hear acknowledgement.
Yeah the e190 could have reported the rto earlier, but their first priority is to perform the maneuver safely, not tell ATC. Having said that, they had to know the airport was busy (atc launching more aircraft behind them) and it wouldn't be that hard to key the mic while they're slowing down and let atc know. I'm not sure how long it was from the time they completed the rto until their attempted report, which was stepped on. I would hesitate to lay blame on the e190 crew without knowing all the details.
@@unpopularopinion8608 The 190 didn't get an acknowledgement of their transmission about the RTO. But... there might not have been enough time to conclude an acknowledgement was not pending. Tenerife happened in part because pilots accidentally talked over each other on the same frequency. Interesting they don't have a system that can warn them about that. Maybe a triangulation thing that sounds (another alarm!) when it gets a square (two transmitters) instead of a triangle. It's also the dilemma we all face at a yield sign. If you stop when the car behind expects you to go, the risk of collision increases. If you RTO when everyone expects you to takeoff, it better be more than one big bird.
@@crimony3054 Cars at yield signs don't have a controller directing them. But there are thousands of airports without control towers. And pilots must ensure the runway is clear before departing. They don't go ahead and takeoff while assuming that the guy halfway down the runway is going to complete his takeoff successfully. (Unless you're at sun-n-fun or Osh Kosh) But that's what this controller did. Assume. And it's tough to blame the pilots because once we give someone else control over our safety we naturally let our guard down a little, its human nature. "Well the controller cleared me for takeoff, we must be good to go." I was cleared for takeoff once but told the controller "no thanks I'll wait for the guy on short final." He crossed the threshold 10 seconds later. Class C airport. Trust, but verify.
That lack of spacing is mind boggling - even if the wake turbulence from an E190 would do little to the beast a 777 is, wouldn't it has overtaken the ERJ once in air?
It’s absurd that radio conflicts like this can still occur. An advanced digital communications system capable of avoiding such conflicts has been possible for decades, so why hasn’t there been any progress in this area? The positional awareness systems were obviously flawed too, by making assumptions without feedback, but the humans designing and programming those systems were ultimately at fault. The radio conflict issue is a known inherent flaw in simplistic radio communications, and should have been eliminated as soon as it was technically viable to do so. Thanks for another enlightening presentation.
Was coming here to say exactly that. It is mindboggling that nothing has been done to sort this - incident after incident have involved conflicted radio calls like this.
There are two major problems with your rather simplistic solution. One is that planes are, well, mobile. They go different places, including to different countries with different levels of wealth. The current system works, so good look convincing the entire world to spend billions of dollars and multiple years ripping out existing infrastructure to go to your new fancy digital system. Not to mention the confusion during the transition period (is that airplane equipped with the new system or the old?) increases the chance of accidents. Two is that digital systems have their own problems. Sure, it's possible to design a system that doesn't have this specific problem, but that will involve a trade-off with other issues it could have. The aviation industry as a whole is *extremely* hyper-suspicious about new technologies, because there have been numerous incidents of some new-fangled technology that had an undetected bug that wound up killing a whole plane's worth of people. So you're going to have a long uphill battle convincing the powers that be that any new communications technology is just as safe and reliable as good old-fashioned AM radio.
@@HiddenWindshield Many advanced technologies have been adopted over the decades. Also, you contradict yourself by calling it “simplistic” and then proceeding to rant about how complex it would be to implement. Being contrary for the sake of it just wastes everyone’s time. Thanks for your rather obvious, and far from unexpected, ‘input’. _SMH_
@@anhedonianepiphany5588 Yes, there have been many advanced technologies adapted by the aviation industry. If you read my post a little more carefully, you'll note that I said it's _difficult_ to do so, not impossible. But make no mistake, it *is* incredibly difficult to get new technologies accepted. _Unleaded gasoline_ is a technology that hasn't been adapted by the aviation industry yet, so when I fly a piston-powered airplane, there is still lead in the tanks. And, yeah, I probably could have worded the complexity part a little bit better. My point was that *you seemed to think* that designing and implementing an entirely new worldwide communication system world would be a simple, cheap process, when it is not.
@@HiddenWindshield "The current system works..." - except when it doesn't, and people die. There are multiple documented fatal crashes where radio conflicts are either the main cause or a contributory factor. Yes, it's not a simple implementation, but to do nothing smacks of complacency, which is not a good look for an industry that says it puts safety first.
Everyone was doing exactly what they were supposed to, except the smaller plane's crew didn't get their reject confirmed. Feel like there should've been something more in place for safety.
Well, the crew gave a radio call that they were rejecting their takeoff. It really isn’t something that the crew would necessarily expect or are required to get an acknowledgment for. They definitely had their hands full performing the abort. In a perfect world, they would have received a “Roger” from the tower. Most pilots anticipate a go when taking off. An abort is always possible, but is definitely unexpected. There is a bit of a shock effect when taking such steps, and training takes over. The captain calls for the abort, and executes the steps required. The first officer verifies that the spoilers have been deployed, the autobrakes are engaged (if installed), and makes a call to tower that they are rejecting. It all happens quickly, and if your transmission is blocked by another, you wouldn’t know it. The crew would be completely unaware that another aircraft had been cleared to takeoff behind them.
When a controller is communicating with more than a single pilot on any radio freq, the opportunity for missed messages is a real problem. I think this was the root cause here.
All this hassle could've been saved by the flight crew having a simple button to press that would set off an alarm or red light or something in the tower to tell/remind ATC that the T/O had been rejected
Yes, and many pileups on fast roads could be avoided if all drivers had a "simple button" in the car that flashed up warning lights on the side of the road to inform following traffic that they have stopped or braked heavily. What I am illustrating is that while your concept is simple, the implementation would be extremely difficult and expensive while providing exactly the same degree of safety that ground radar is supposed to provide. Ground radar is supposed to inform controllers when a runway is still occupied, and if a traditional ground radar had been in use the controller probably would have seen that the small jet had not cleared the runway and so would not have given the takeoff clearance. But the traditional "dumb" ground radar PPI display had been "improved" with a system that had "intelligence" and erroneously displayed the runway as being clear when it was not. The solution is to fix the technical design error so that the ground radar system works as it should.
Oxcart have 0 hours studying aviation while Dave has studied aviation for hundred hours just by looking from the argument and the counter. Great explanation
Isn't there one additional call that was also missed? When the 777 was given its takeoff clearance, the E-190 was obviously still on frequency. Sure, the E-190 crew were probably quite busy with the rejected takeoff, but not only did they miss that they didn't get an acknowledgement for their rejected takeoff call, they also didn't realize that another aircraft was given a takeoff clearance for the same runway that they were still on, and they didn't catch that aircraft's readback which would repeat that very same information (something like "Air Canada 123, winds calm, runway 06L, cleared for takeoff" followed by "Cleared for takeoff 06L, Air Canada 123"). In the swiss cheese model, that adds yet another layer that also happened to align in this incident. Glad it all ended in a very minor nuisance! And thanks for the excellent video!
Their communications overlapped each other like Tenerife. Therefore one pilot could not hear the other pilot nor could the controller overhear them both.
@Yurgon, the way I understood it, the E190 heard the 777 get cleared for takeoff and immediately realized they hadn't reported their rejected takeoff. They then attempted to report said rto but it occurred as the 777 was reading back their takeoff clearance. The controller should have noticed the two simultaneous transmissions. Neither plane would have been able to tell their tx was blocked. Bottom line the controller issued the 777 takeoff without confirming the e190 was clear of the runway.
This one put me over the edge on this conclusion: the tech that runs air traffic radio needs to be replaced with a version that allows everyone broadcasting at once to be heard.
There are cues that transmission was stepped on and the E190 pilot should have repeated the call when they didn't get acknowledged by ATC. That said I'm not saying the system can't be improved.
@@JamesF0790 doesn’t matter. A system that relies on noticing something subtle like that is idiotic. The entire possibility of being “stepped on” needs to be abolished completely. It should sound like a conference call if multiple people start talking at once.
@@MegaBrokenstar It's not idiotic, it just requires mic discipline and to pay attention. The alternative is to upgrade EVERY SINGLE RADIO at once. Every single tower, every single plane, all of them at the same time around the whole world. And you won't get much benefit from it because instead of getting the transmission stepped on it'll just turn into a jumble of voices.
This is a complicated situation but one question is: why did one automatic system say the plane was airborne when it was definitely still on the ground??
He explained it in the video but both planes automated systems said the planes were in the air. The one system told the other they were in the air from the planes own signals. The other system thought okay they are In the air. By the time it realised they wasn't and created a conflict it was all over. The whole thing lasted less than a minute
The pilot of the smaller jet was in error, by not repeating on no reply from ATC. If he had done so, then probably the 777's pilot would also be aware. And if ATC appears to be not responding at all, it seems sensible to me to take initiative and clear the runway in a safe manner, just by looking around and finding a spot to park safely. Since he could hear that the 777 was in the process of being cleared for take-off. Also, the 777 pilot should hold until he visually clears the runway, if the weather allows for that. Workload? Well, if you just stopped after an aborted take-off, first thing to do is inform ATC. What could be more important than asking for confirmation, at that point?
Question- when a flight is cleared for takeoff, besides identifying the plane he’s talking to, does the ATC repeat which runway they’re cleared to take off from?
Strange that the TWR controller was sitting with his back to the runway he/she was controlling... The controller should always have good visibility on the runway(s) he/she is controlling. Nice simulation.
I am in awe of air traffic controllers. It must take a very special brain to be able to keep all that information separated and logical. I couldn't do it if it was the last job in the world.
At 6:03 you're unfortunately incorrect... At least for US atc. If the planes have divergent departure paths, atc can clear the next plane before the previous has rotated. I don't know what amount is required, but i think it 3k or 6k feet.
Something like this happened to a family friend in the 1980's. Just on a much smaller scale. He was taking off from an uncontrolled airport called Nut Tree in California. He was flying a Boeing Stearman a 1930's era open cockpit, 2 seat trainer bi-plane. As the plane is a tail dragger it is not easy to see directly forward. When taxiing the pilot weaves back and forth to see where they are going, but on take off you just have to hope noting is in the way until you gather enough speed to fly the tail. In this case there was a plane landing, and a Cessna 172 taking off ahead of him. The friend watched the 172 start its takeoff run then he lined up, waited long enough for the Cessna to take off then added power. But the Cessna had rejected its takeoff and stopped on the runway. Our friend didn't see this until the tail started to fly but by then it was way to late. The propeller of the Stearman cut the Cessna's fuel tank open and a fire broke out at once. No one was killed but it was a pretty scary crash.
Not really. there was a lot that went wrong here and the transmission being stepped on was only a small part of it. If the E190 pilot had repeated the call after not getting acknowledgment it wouldn't matter for example
You said that the tower clearing the 777 for takeoff while the e190 was still rolling... Is routine and expected of him 6:50. NO IT'S NOT. It might be routine for him..but operationally he has to make sure it's taken off and minimum separation is met.
When a takeoff is aborted, the crew should broadcast that information twice or more instead of its one transmission possibly being blocked by another transmission?
Airliners don't have brake pads as such, each brake works more like a multi-plate motorcycle clutch. They do get very hot in a rejected take off though and should be inspected before flying. These missing radio transmissions do seem to be a common occurrence and there should be some way to resolve this. The obvious way is to repeat if you get no reply.
That's interesting, didn't know that but makes sense given the force needed to slow a plane. Watched an A380 brake test simulating an overloaded plane with minimum brake condition. A fire started but the test was a success.
The tyres also have fusible plugs; hot brakes can cause a plug to blow out. Happened to me once on a VC10 after an overweight landing; a tyre plug shot out like a bullet. Luckily the fire crew had all the pax well away from the mainwheel area.
It never ceases to amaze me that aviation continues to rely on awful, primitive radio technology from half a century or more ago. I realise it's an exceptionally difficult transition to make, but nobody seems to even consider or discuss the role of radio technology when looking into preventative measures for these incidents.
There are indeed digital radio modes that can be used these days to pass messages and clearances between aircraft and ATC. But VHF AM voice communication has been the standard for about a century and is usually pretty reliable. One thing that has changed is that the early VHF radios were rarely transmitting on exactly the same frequency due to small errors in the transmitter. The whole reason why AM was chosen rather than FM is that if two AM radios transmit at the same time, then if they are on slightly different frequencies any receiving station will hear a distinctive whistle or beat note making it obvious that two stations were transmitting at the same time. FM receivers on the other hand will exhibit a "capture effect" and if two stations are transmitting on nearly the same frequency you will only hear the stronger station, which i why AM is better for this purpose. These days aircraft radios are far more accurate and all will transmit pretty much on the exact frequency selected, so you no longer get a beat tone and it is not always obvious that there is a second transmission. Increased accuracy has reduced safety in other areas as well - it used to be the case that even if two aircraft were flying toward each other at the same altitude along the same route, they would be unlikely to collide because they were unlikely to be exactly on course due to navigation errors. Nowadays with improved navigation equipment, navigation errors are likely to be meters rather than miles off course, making collisions more likely (until TCAS came along).
There is a crucial lesson here that you missed: the radio systems of the planes are obsolete. The half-duplex communication of these radios was absolutely unavoidable in the 1930s when they were first installed, but full-duplex communication is now usual in almost every application except this one. When was the last time that you didn't hear something on the phone, cellular or otherwise, because you were talking at that time? We now even have conference calls with dozens of participants and with no problems like this one. In any voice communication system designed less than 30 ago the possibility of more than one person talking at the same time is handled nicely, and if it becomes necessary, alarms can be fitted to signal lost messages due to congestion. When the radio systems of planes were first designed, digital communications did not even exist in science fiction. Now almost no communications in the world are non-digital, except AM radio, FM radio, and plane communications.
There are LTE 4G radios like the Icom IP501M. It would require probably some kind of safety enhancement for use in an aeronautic environment, but nothing undoable.
Controllers should be relying on some kind of positive confirmation on take offs, other than looking through the windows and other colleagues' armpits. What if the visibility is poor? How can either a controller or following plane pilots be sure the runway is clear? We've seen how many important radio transmissions have been lost due to interference in other episodes. Aviation industry is stuck in Tesla's and Marconi's time. Of course, simplex radio must be there for redundancy as a simpler and a bit more reliable alternative, but for security's sake new protocols and communication technologies must be developed and deployed at last.
Important distinction: ‘departure clearance’ instructions after take-off, often given before a ‘take-off clearance’ which is ‘cleared for take-off’. More than one aircraft can be on the active runway for departure at a time, intersection departures. We call this ‘racking and stacking’. In Tenerife low-visibility prevented line-of-sight confirmation of aircraft position, and language difficulties also caused problems. None of these things were factors in this case. Fortunately the 777 has huge stopping power. I think a key take-away from the video is that PILOTS are the last barrier to accidents happening, not controllers.
I like that you have the video end with the landing as it should have been for the flight in question. So even if there was a crash, the video ends with things as they should have been.
A mini Tenerife in Toronto is a horrifying thought. Fortunately you had a few factors both incidents did not share: Tenerife had thick fog roll with no ground positioning system, a skeleton crew on that weekend and a senior Dutch airline pilot on their tarmac with the patience of a tea kettle.
Mentour has a great video about it, with a bit more details about it, although everything is mostly covered here. Very complicated incident, all these systems in place but this situation couldn't be caught.
Very interesting. Initially I did thing ATC error, but when you went through the detail it seems to me like there was really no-one at fault. If there had been a collision then ATC would probably have got the blame but if your screen says a plane (that is on the ground) is in the air, (worse) you don't recieve a critical transmission and you can't see the runway/that part of the runway nor are you expecting trouble what are you supposed to think. I'm surprised the 777 managed to stop. Still, at least this video had a happy ending...except (perhaps) for the bird!
imho the one at fault is making someone responsible for two runways while he can only see one of them. Probably meaning the airport itself is at fault.
If shaving off 30 seconds is so critical, then it needs to be compensated for by putting an extra set of eyes, or two, in the tower to help deal with the additional workload. This shouldn't represent a huge cost when compared to the value of the machinery and lives in motion.
It's the weirdest to hear that in 2020 we still have archaic radio comms like this and also that a B777 wouldn't have a sensor to indicate obstacles on a runway.
Thanks for the content, usually the Canadian controllers wait until the nose wheel lifts off that way they would know the V1 is way back no matter what.
Maybe a stupid question, but is there a way where radio messages sent to control at the same time could be buffered, and then played sequentially, rather than cutting off the second message?
No. That's not how radio works, it's a signal and frequency. Microwave signal. In order add buffer you need the receiver to be slow as well. But here's the logic, if two signals colliding each other that would interfere the clear signals and would cause the ATC to hear distorted noise.
7:33 Seems this could have been completely avoided if one or both pilots remembered to follow the basic rule of radio communication on a shared frequency: Listen before you key (the microphone).
Even if everyone listens first, sometimes two people key their mic at the same... blocked. Even worse if they also end their transmission simultaneously, because only a third party hearing the garbled transmission knows that it happened. Usually whomever unkeys first hears the end of the other's tx so they know they were blocked.
In regards to safety issues - it seems that the audio quality of ATC transmissions, or at least what can be heard on a video about aviation or even a live plane spotting broadcast, is rarely of clear audio quality. I have to read subtitles when available to understand clearly what’s being said. Also, as it relates to your presentation, I’m surprised that it’s still possible for a pilot’s radio communications to be stepped on. Is this being evaluated for improvement in any way? I understand that confirmation read-backs of communications are crucial, but it seems quite risky to rely on pilots & ATC’s to never forget to confirm a message. Also, it seems that the standard ATC expressions “takeoff clearance” & “cleared for takeoff” - related, yet meaning different actions, could use a change to eliminate confusion for pilots. They might also misinterpret these if they experience poor audio quality. Also, I have a question: besides ATC identifying the plane they are communicating with, do they also repeat the runway again that a pilot is cleared to takeoff from? That way, a pilot in a similar situation to this video might pay closer attention to ATC communications with other pilots, if they hear their runway being called out.
I was wondering why the E190 pilot, not having received a confirmation for the rejected takeoff transmission, did not try again. Or was the timing too short for that?
I mean a lot of little things went wrong 1. The 777 needed to visual verify that the plane was airborne before it took off (if able) 2. If the pilot got no acknowledgement from ATC on an abort, they should've attempted their transmission again at least 15 seconds after the failed call 3. There should be a fallback system that let's other planes know that they're still on the ground. That system should not be hard-coded, and should change back to on ground if it detects any braking or the speed goes back under the threshold
Great that you cover lesser known and non tragic events. Obviously the pilot monitoring on the Embraer should have followed up the lack of acknowledgement of his rejected take off call out but this there should be some way to eliminate simultaneous transmissions on aircraft frequencies. These radio calls can certainly become mundane but they are extremely critical. Maybe tie the A-SMGCS to the WoW switch. Also when you bring any vision reducing factor into this scenario this system looks to be set up for an eventual disaster. Rare and unlikely? Sure. But is that good enough? Burt Rutan suggested a synthetic-aperture radar image projected onto the windscreen. Theoretically the pilot flies the same in zero visibility as VFR. Could this be possible?
ATC gave 2 aircraft take-off clearances based on a flawed systems design, without confirming visually ATC then directed their attention to another runway which is around 4 kms away. Toronto is notorious for 1 controller trying to do everything. I’ve had the same controller giving IFR clearance, taxi clearance and tower clearance all at the same time. This is an accident waiting to happen, NAV Canada is not adequately staffing YYZ and is not seeing the bigger issue when 1 controller tries to do everything.
None. Both aircraft crew would probably filed a report to their airline about this incident and the airline will investigate it and with conclusions they will probably increase the pilots training on communication and also give a recommendation to the involved airport to improve their equipment even more.
Love the channel. Request. When you mention a runway “270L“ could you show a map of the airport and show which runway and the direction the particular plane is flying in Ta over and out.
As soon as you said they talked over each other, I thought Tenerife. That was too similar, despite it being 50+ years later. If it hadn’t been clear, this would have been *almost* the same accident.
So what changes were implemented to avoid such a situation from occurring again? *Lesson learned* for me, personally as a passenger: avoid busy airports if you possibly can. I wonder, can't they have some traffic lights installed at the start of each runway? Linked to the actual ground radar, not some other AI system. So if the groundradar still detects the plane taking off, the lights say 'stop' for the next plane waiting to take off. Of course such a system should be used as a final check after receiving the actual take off clearance from ATC.
Was there something wrong with the ERJ model or was that just me not seeing things correctly? I know the wings sit quite low on the jet but the wings in some shorts looked really bent up
Thank goodness - I thought of Tenerife too! Seems like ADSB should have shown two planes on the runway, but I'm pretty ignorant of that system... It's great you cover near misses too because just as much can be learned at a far lower cost.....
It just wasn't another Tenerife because the Canadian plane aborted takeoff as it could see the E-190 still in the same runway, as there was no thick fog or thick mist covering the runways like in Tenerife.
It's obviously settings used by the automated ground safety systems. By the way, if there was only one runway why was the controller not in the seat facing that runway instead of to the side and rear of the control tower?
6:10 you said for the uninitiated a takeoff clearance is not permission to takeoff. I’m a pilot and I guess every time the tower tells me cleared for takeoff I shouldn’t have taken off then 💁🏻♂️ so maybe you meant IFR departure clearance which is not a takeoff clearance
The preliminary reaction was to blame the ATC, but it was actually the system yielding false information. It is a good example of how jumping to conclusions without all the facts is a mistake.
I think the major causes were the unintended consequence of the two ground radar systems which were not designed to interact with each other, and the 190 pilot failing to repeat his departure information when he might have known that there had been a cross-transmition. The seating position of the controller, having to stand up to look at the other runway, might also have been significant and maybe that needs to be considered in a tower reconfiguration.
yeah, so much money spend on building a special tower for the ATC so they can see what's going on and then put the controller on the opposite side so he can't see what's going on...
I enjoy that you cover not well know accidents. It seems like everytme I watch a mentour video it's about an accident that has already been covered by air crash investigation / mayday or other major documentaries. It isn't as interesting or fun to hear about accidents I already know about. Thanks
I feel mean saying it cos Mentour is obviously a nice guy and a professional - deeply invested in the notion of learning from history to improve safety and educating a wider audience on those issues. At the same, I sometimes find the level of detail he incorporates makes me wilt a bit. Also while I am the first to abhor blame culture where people operating within it become afraid to own up to mistakes for fear of sanction, I do feel that that has to be balanced with recognition of the degree of culpability of each and every party that was in some way involved with an incident. There have been times where - unlike our delightful host on this channel who generally prefers to ask us what we think rather than pronouncing on it himself - Mentour is happy to indicate a preference for any other possibility than pilot ineptitude, laziness, ill preparedness etc, commonly euphemistically referred to as pilot error which in fairness I think also includes less proscriptive failures. Naturally, there are some aspects of flight which can be influenced by very human qualities which make it a grey area as to whether they excuse, or otherwise, poor performance. In Green Dot, I recently endured a fair amount of criticism for daring to suggest that two Air France pilots, while flying from New York to Paris, on the approach to their destination inadvertently input opposing commands into their respective yokes, should face consequences, albeit I did not even obliquely imply they should be hung, drawn and quartered, or even lose their jobs. Incidentally, their comically poor management caused sufficient confusion and loss of control to bring the aircraft as near to crashing as it's possible to do, without actually crashing. Everyone else dismissed that option as, since the flight was a "graveyard shift" (which no American airline operated for that reason) the pilots were "fatigued" and therefore blameless. Similarly, Mentour felt that the pilot in command of TransAsia Airways Flight 235, who instead of switching off the malfunctioning engine in response to it flaming out on take-off, shut down the one which was still working. You can easily find the result of his actions all over the 'net, with dramatic and horrifying footage of the plane, banked at 90 degrees as it flies over a viaduct, its left wing tip first hitting a car travelling on it and then the guardrail, before disappearing out of shot although we are all to aware of the tragic outcome. Mentour ascribed most of the blame to the airline for failing to provide adequate competence checks and training which I disputed since Transasia could show that he had recently been tested which was failed so was given further instruction resultig in a pass of the retest. Well excuse me, I really don't think any more could have been done by the airline and that this was just individual incompetence. As said at the beginning, I don't like blame culture but denial of responsibility is just as bad - which you don't get here and, along with the more succinct and pithy script and engaging delivery by Mini Aircrash Investigation's creator - that is why I much prefer his channel to any others!
Mentour provides a professional pilots insight into the accident that other shows may not have. His production value is also very good. In short, both channels do what they do very well
Mentor covers the well known crashes because he focuses on what happend and how it changed the airlines and how one crash saves alot of lives
Good points, Ive noticed this also!!!🙏👍🛫
I think you mean incidents. Not accidents.
You are becoming one of my favourite aviation channels due to the fact that you cover much lesser known events being a TH-camr myself means I don’t get much time to watch others content so I truly appreciate your efforts!
As an ATC something you may not know is giving takeoff clearance we use cleared FOR takeoff and landing it’s cleared TO land. You won’t ever hear cleared to takeoff or cleared for landing. Really enjoy your videos!!
It’s definitely going to be an operational error on the ATC. We are human like everyone else but we hold ourselves in a higher regard.
Is it too Naive to believe that "Transponders" could be used to Identify Aircraft on those Runways and Taxiways so that ATC can see their Actual positions on the Screen? Or does this happen? Huge admiration for you guys at ATC - such responsibility!! When talk about "extra runways" are ATC Personell ever consulted?
oh, hm interesting. nice to see an ATC point of view if you were a former ATC that is. "as an ATC" oops misunderstood that part, my bad bud
@@MaverickSeventySeven there are ground radars which help ground and tower controllers, they do use the transponders
@@Bartaaron04 Thank you!
Yeah we are humans because no one was killed.SMFH
Whenever automation lies about its current state, because of a design decision, it is a bad design decision.
Really interesting and frightening video. 👍
Yep, there's no point saying I'm at x, when I'm really at y. The makers of those design decisions need someone to have a word. I hope that that system has been changed now where the state given is the actual state.
The rationale was good though. The "in-air" flag is supposed to mean "if I'm not in-air, you can ignore me for the purpose of TACAS advisories and ATC conflict advisories, I'm taxiing or parked". For that purpose a plane in takeoff phase *is* "in-air" and it's reasonable to broadcast as such. Doing so could allow TACAS to warn a plane that's doing a go-around that someone else is about to take off into their path, for example.
The problem is that the flag must've been poorly specified. So the ground runway incursion system assumed it could use the in-air flag to ignore aircraft. But in reality the in-air flag was the "not definitely still on the ground" flag. In-air = false meant "definitely on ground" but in-air = true did NOT mean "definitely in air not on ground".
Not enough attention was paid to the boundary conditions.
And it's clear the runway incursion system wasn't tested adequate either. Because this should've come up in testing with high speed taxi, or with one aircraft about to land on an occupied runway.
People are misunderstanding these systems - they aren’t really designed for this scenario in the first place, and are NOT used for general ATC operations on a normal basis; they’re something in the background that’s “there” and the normal procedures and safety margins are what keeps aircraft safe on a normal basis.
Most of the ground monitoring equipment is used for inclement weather, fog, etc. For example, if one aircraft had been back-taxiing while another entered the active runway, the system would have worked perfectly fine, THAT is what it was designed for.
they should RAAS andthe CGYAS be replaced by ATSD, with planes also having theirown ground radar, upgrade RAAS with a warning, " AIRCRAFT STILL ON RUNWAY, ABORTABORT> i mean automation isnt bad at al As long it is implemented correctly and done good.
Great work! You've really improved alot of the production aspects since you first started, today was a good day to return to watching your videos.
Thank you!
My thought process: "Ah, ATC error. No, wait, _pilot_ error. Uhm.. no, system design error!"
In conclusion, systems could be better designed, ATC could've kept better track of the planes...
But I still think the biggest fault lies on the pilot (or whoever took care of the radio) to not follow up when they got no read-back. Colliding radio calls seem to be common, they shouldn't have let that go, especially in a situation like this. (Maybe they were about to? After all, everything happened quite fast.)
I'm no airline pilot but I would think if you would hesitate for any clearance you're not sure about, it would definitely be a takeoff clearance. Seems complacency kicked in a little bit.
As a cabbie from the radio dispatch era, I never assumed my dispatcher heard me unless they acknowledged me directly. 7-4-0 CHECK.
Maybe Im being naive here, but I thought, no ATC was supposed to clear another plane to land or for takeoff for a runway, until they had confirmation, the runway is clear. I mean, he just assumed, the first plane had taken off. He didnt get radio confirmation, he didnt get up and check visually, nothing. He just assumed.
But apparently I also assumed wrong. Already a nervous flyer, this doesnt really make me feel better about it.
I agree. Systems did what they were programmed to do, which left the chance for just this eventuality. My time in the navy taught me no message is received unless properly acknowledged. They pilot entered an abnormal situation by rejecting the takeoff, so it should have been very important to verify his status report had been received.
Thank you for documenting these stories. Often the media forgets these events, just before no fatalities occurred. However, these stories are really important to aviation safety and for anyone who loves this industry. Great video. Your channel is awesome!. Looking forward to your next video.
Pilot of E190 should have repated his call to controller after receiving no acknowledgement.
Agreed. Should have made that well known, in hindsight. Except, he made the call, and you don't always get acknowledgement. Just good fortune that the 777 pilots had 20/20 vision. Nobody was at fault in my opinion, everybody did what was expected of them, just bad circumstance lead to a potential disaster that didn't come to fruition, thankfully.
Appears you have never done a rejected takeoff
I noticed the similarities between this incident and Tenerife.
I really like your knowledge and articulate way of narrating your videos.
Thanks Mini man 😘
First point is that the number of things that went wrong here is truly impressive and by default makes it hard to pin causes(not blame) anywhere. Here are my two thoughts.
1) The 777 needed to visually verify the other aircraft as airborne. If I can spot a 150 5,000 feet down the runway when I'm setting up for my roll, then a small jet can very easily be seen.
2) Though the pilots of the smaller jet where terribly busy, there is a "stepped on" audio que that all pilots should be familiar with. It's not like it's a terribly uncommon occurrence. A reception of the abort call out until after the step on que stopped might have assisted.
Again, these are just two thoughts on contribution, not blame. It's easily understood that these are two small things often overlooked every day and the pilots where in a super high workload of flight.
Two very good points. A 90 seat regional jet may be small compared to a 777, but hardly "tiny" as described in the video. It's about the size of a DC9. The pilots in the 777 should have had no problem seeing that it hadn't taken off.
This comment makes absolutely no sense whatsoever. It’s not even proper English.
It sounds like the person writing it might be a pilot himself, but I find it hard to believe a person with such poor language skills could achieve a pilot’s license.
1. No it doesn't - that is the controller's job and he must not issue take-off clearance to the B777 until it is confirmed.
2. The garbled transmission communicating the abort is simply communication - it is not structural to the ATC safety net.
It the controller said "Cleared take-off" to the B777 it is his error - he had not confirmed the runway was safe to use before doing so.
@@johnbolwell5969 And here we get why I listed these as thoughts, not as definitive reasons or as causes. In close insidents it's important to look at the issue from all available perspectives and see what could have changed the outcome.
There is a concept on aviation that can be boiled down to "maximum available safety." When vfr is present and an ifr aircraft is in that zone it is desired for that aircraft to maintain what they can of their own VFR traffic scan. If you listen to ATC recordings or fly through tml or arr/dep airspace you'll likely hear a transmission like this:
Ifr callsign, traffic at your three, 500 below, a vfr contact. They're looking for you.
Tml, callsign, afirm *looking for traffic*
Now they are ifr. Spacing and separation is no longer their responsibility. But because the safety conditions allow it, the ifr will also perform visual safety procedures.
Had this happened on the ground the incident would have amounted to a simple call of "negative, traffic on runway."
Do I blame the 777 pilots. Of course not. Strictly speaking they where following clearance that should have given them traffic avoidance. They where in a stupidly high workload faze of flight.
However could the situation have been a avoided like this. Yes. Thus it serves as a valuable reminder for pilots to stay vigilant to the maximum degree available and possible. It serves as valuable advise that helps fight complacency.
@@Fkruus Sure, I get that. The visual scan of all traffic is good practice and, as in this case, made the difference - we'd call that "belt & braces" but if we are talking about where formal responsibility lies, for IFR traffic it is firmly vested in the ATC system. Safety should not occur by accident; it should be the natural result of proper application of ATC procedures.
You wouldn't hear that call in the London Terminal area - VFR not allowed. At Heathrow we do give traffic calls to IFR when we do multiple arrival streams but it's not the norm - the r/t loading is already saturated.
The problem here is the use of systems for multiple functions they weren't designed for. And if a system is designed to do two completely different things there are also problems sometimes when those two parameters overlap or come into contact. There is a compromise occuring that gives precedent to avoiding collisions immediately after taking off instead of on the ground. And any other system dependent on a flawed system is also flawed.
I'm digging your opinion, makes sense to this landlubber!!!🙏👍🛫
What you called a takeoff clearance is actually an airways clearance. The ‘clear for takeoff’ is the takeoff clearance.
its called departure clearance in the UK
The chief issue here is that the E190 pilots did not get a tower confirmation that they were rejecting take-off. If the tower heard them, the pilots would have received acknowledgement from the tower...
I'd like to actually hear that transition of calls because there could have been a lot of radio chatter where the E190 couldn't repeat the call. The 777 should have been able to confirm that there were no aircraft on the runway prior to getting over 100 knots though. You can always use your eyes, you can't always use the radio.
@@RindiculousfunI think it was just after 6:15 in the morning
I was watching the news a few weeks back and they mentioned this. However, it was in the break room at work, so I couldn't really hear the details due to other sounds in the room.
Thank you for telling the story :).
The so called "Take off clearance" mentioned at time 6:05 in this video is actually called a "departure clearance". The words "take off" are only used in connection with the actual clearance to start accelerating and taking off. Pilots who have only received their departure clearance will always hold their position on the runway until they receive a take off clearance containing the magic words "take off". In this case however, after receiving their departure clearance, they accidentally also received a take off clearance
Because of Tenerife.
My son is a federal air traffic control supervisor and I fly fairly often. I have a deep appreciation for how complex their jobs are, and I marvel at their abilities to juggle everything in their heads while they talk to multiple aircraft. I believe the causes of this near miss are the smaller jet not confirming their report to the tower of the rejected takeoff when the tower didn’t acknowledge it; a poor system design that allows one communication on the same frequency to cancel out another (a major contributor to the Tenerife accident), perhaps the controller getting in the routine of not confirming that a plane took off; and a tower design that doesn’t allow the controller to see the runways easily. The last was a major cause of that LAX runway collision in 1991- the controller’s view of the runway was obscured by the tower design. Great channel!
The biggest contributing factor was (in my opinion) the bird that hit the E190.
Excellent re-creation and presentation!! Thanks for your work on this incident!! 👍✈✈👍
I think the biggest contributor to the accident was definitely the flippin' bird XD
6:08 i thought that would be a departure clearance. From what i learned the word takeoff should never be used, except for the actual takeoff clearance permitting to start the takeoff roll
I agree, I've never heard of an ifr clearance referred to as a takeoff clearance. Not to mention major airports have a dedicated clearance delivery freq for this and it occurs before the plane even taxis out. The tower might have some slight amendment to the departure routing/ assigned altitude but that would normally be issued in conjunction with the actual takeoff clearance.
@@unpopularopinion8608 yeah, thats what i understood as well.
What i hear quite frequently when it comes to amended departure clearances or "when airborne" instructions is like "Delta 1234, fly heading 320, runway 28 cleared for takeoff", but it could also be issued as "Delta 1234, on departure, fly heading 320, runway 28 line up and wait". Never uses the word takeoff though.
This is right. A take off clearance is the words “cleared for take off” and it tells a pilot they are able to take off. I think the wording of the video is just wrong. “Departure clearances” are part of the standard IFR clearance “cleared Sydney via DOSEL planned route DOSEL1 departure” etc.
6:07 If I'm not mistaken, the takeoff clearance is "[callsign] cleared for takeoff" the clearance of how to fly from 1 airport is called the departure clearance
According to mentour pilot's video, he did say "A-C-A606 cleared to enter runway 06L and cleared for takeoff"
Were any changes made after this?
Very clear, complete and informative. Congrats
Control towers were designed at the early ages of commercial fligt to overlook all takeoffs and landings. For some reason, nowadays, Tower ATC are more focused on planning rather than lookin through the window.
Pilot of the 190 did not hear the controller acknowledge his rejected takeoff... because the controller never heard it. Everyone reads back everyone else's transmissions to assure they're communicating. What's the smaller risk -- that the jet will crash because a bird fouls one engine at takeoff or that jets will collide because one pilot rejects a takeoff and fails to communicate it to the tower? Fails to communicate is the correct terminology because the rejecting pilot dropped the ball when he didn't hear acknowledgement.
Yeah the e190 could have reported the rto earlier, but their first priority is to perform the maneuver safely, not tell ATC. Having said that, they had to know the airport was busy (atc launching more aircraft behind them) and it wouldn't be that hard to key the mic while they're slowing down and let atc know. I'm not sure how long it was from the time they completed the rto until their attempted report, which was stepped on. I would hesitate to lay blame on the e190 crew without knowing all the details.
@@unpopularopinion8608 The 190 didn't get an acknowledgement of their transmission about the RTO. But... there might not have been enough time to conclude an acknowledgement was not pending. Tenerife happened in part because pilots accidentally talked over each other on the same frequency. Interesting they don't have a system that can warn them about that. Maybe a triangulation thing that sounds (another alarm!) when it gets a square (two transmitters) instead of a triangle.
It's also the dilemma we all face at a yield sign. If you stop when the car behind expects you to go, the risk of collision increases. If you RTO when everyone expects you to takeoff, it better be more than one big bird.
@@crimony3054 Cars at yield signs don't have a controller directing them. But there are thousands of airports without control towers. And pilots must ensure the runway is clear before departing. They don't go ahead and takeoff while assuming that the guy halfway down the runway is going to complete his takeoff successfully. (Unless you're at sun-n-fun or Osh Kosh) But that's what this controller did. Assume. And it's tough to blame the pilots because once we give someone else control over our safety we naturally let our guard down a little, its human nature. "Well the controller cleared me for takeoff, we must be good to go."
I was cleared for takeoff once but told the controller "no thanks I'll wait for the guy on short final." He crossed the threshold 10 seconds later. Class C airport. Trust, but verify.
@@unpopularopinion8608 And I always check my rear view when approaching a yield to see if I can take it or leave it, or if I have to push it. 😎
That lack of spacing is mind boggling - even if the wake turbulence from an E190 would do little to the beast a 777 is, wouldn't it has overtaken the ERJ once in air?
Since they where going opposite directions it probably would not matter
Mathieu got it here, one goes one way, one keeps goes the other
I'm not so sure that's the problem here. The 777 and ERJ faces against each other as Matthieu mentioned.
It’s absurd that radio conflicts like this can still occur. An advanced digital communications system capable of avoiding such conflicts has been possible for decades, so why hasn’t there been any progress in this area? The positional awareness systems were obviously flawed too, by making assumptions without feedback, but the humans designing and programming those systems were ultimately at fault. The radio conflict issue is a known inherent flaw in simplistic radio communications, and should have been eliminated as soon as it was technically viable to do so.
Thanks for another enlightening presentation.
Was coming here to say exactly that. It is mindboggling that nothing has been done to sort this - incident after incident have involved conflicted radio calls like this.
There are two major problems with your rather simplistic solution.
One is that planes are, well, mobile. They go different places, including to different countries with different levels of wealth. The current system works, so good look convincing the entire world to spend billions of dollars and multiple years ripping out existing infrastructure to go to your new fancy digital system. Not to mention the confusion during the transition period (is that airplane equipped with the new system or the old?) increases the chance of accidents.
Two is that digital systems have their own problems. Sure, it's possible to design a system that doesn't have this specific problem, but that will involve a trade-off with other issues it could have. The aviation industry as a whole is *extremely* hyper-suspicious about new technologies, because there have been numerous incidents of some new-fangled technology that had an undetected bug that wound up killing a whole plane's worth of people. So you're going to have a long uphill battle convincing the powers that be that any new communications technology is just as safe and reliable as good old-fashioned AM radio.
@@HiddenWindshield Many advanced technologies have been adopted over the decades. Also, you contradict yourself by calling it “simplistic” and then proceeding to rant about how complex it would be to implement. Being contrary for the sake of it just wastes everyone’s time. Thanks for your rather obvious, and far from unexpected, ‘input’. _SMH_
@@anhedonianepiphany5588 Yes, there have been many advanced technologies adapted by the aviation industry. If you read my post a little more carefully, you'll note that I said it's _difficult_ to do so, not impossible. But make no mistake, it *is* incredibly difficult to get new technologies accepted. _Unleaded gasoline_ is a technology that hasn't been adapted by the aviation industry yet, so when I fly a piston-powered airplane, there is still lead in the tanks.
And, yeah, I probably could have worded the complexity part a little bit better. My point was that *you seemed to think* that designing and implementing an entirely new worldwide communication system world would be a simple, cheap process, when it is not.
@@HiddenWindshield "The current system works..." - except when it doesn't, and people die. There are multiple documented fatal crashes where radio conflicts are either the main cause or a contributory factor. Yes, it's not a simple implementation, but to do nothing smacks of complacency, which is not a good look for an industry that says it puts safety first.
This video was great and shows just how quickly things can go wrong!
Everyone was doing exactly what they were supposed to, except the smaller plane's crew didn't get their reject confirmed. Feel like there should've been something more in place for safety.
Well, the crew gave a radio call that they were rejecting their takeoff. It really isn’t something that the crew would necessarily expect or are required to get an acknowledgment for. They definitely had their hands full performing the abort. In a perfect world, they would have received a “Roger” from the tower. Most pilots anticipate a go when taking off. An abort is always possible, but is definitely unexpected. There is a bit of a shock effect when taking such steps, and training takes over. The captain calls for the abort, and executes the steps required. The first officer verifies that the spoilers have been deployed, the autobrakes are engaged (if installed), and makes a call to tower that they are rejecting. It all happens quickly, and if your transmission is blocked by another, you wouldn’t know it. The crew would be completely unaware that another aircraft had been cleared to takeoff behind them.
When a controller is communicating with more than a single pilot on any radio freq, the opportunity for missed messages is a real problem. I think this was the root cause here.
My wife told me some time ago to stop talking about these great aviation videos I keep watching. It freaks her out!! 😁🤣😅
So stop talking to her about it. Send her a link instead bud
All this hassle could've been saved by the flight crew having a simple button to press that would set off an alarm or red light or something in the tower to tell/remind ATC that the T/O had been rejected
Yes, and many pileups on fast roads could be avoided if all drivers had a "simple button" in the car that flashed up warning lights on the side of the road to inform following traffic that they have stopped or braked heavily. What I am illustrating is that while your concept is simple, the implementation would be extremely difficult and expensive while providing exactly the same degree of safety that ground radar is supposed to provide.
Ground radar is supposed to inform controllers when a runway is still occupied, and if a traditional ground radar had been in use the controller probably would have seen that the small jet had not cleared the runway and so would not have given the takeoff clearance. But the traditional "dumb" ground radar PPI display had been "improved" with a system that had "intelligence" and erroneously displayed the runway as being clear when it was not. The solution is to fix the technical design error so that the ground radar system works as it should.
Oxcart have 0 hours studying aviation while Dave has studied aviation for hundred hours just by looking from the argument and the counter. Great explanation
situation awareness is vital for pilots, know where the aircrafts are around you, especially the ones at the front and behind.
Isn't there one additional call that was also missed?
When the 777 was given its takeoff clearance, the E-190 was obviously still on frequency. Sure, the E-190 crew were probably quite busy with the rejected takeoff, but not only did they miss that they didn't get an acknowledgement for their rejected takeoff call, they also didn't realize that another aircraft was given a takeoff clearance for the same runway that they were still on, and they didn't catch that aircraft's readback which would repeat that very same information (something like "Air Canada 123, winds calm, runway 06L, cleared for takeoff" followed by "Cleared for takeoff 06L, Air Canada 123").
In the swiss cheese model, that adds yet another layer that also happened to align in this incident.
Glad it all ended in a very minor nuisance!
And thanks for the excellent video!
Their communications overlapped each other like Tenerife. Therefore one pilot could not hear the other pilot nor could the controller overhear them both.
@Yurgon, the way I understood it, the E190 heard the 777 get cleared for takeoff and immediately realized they hadn't reported their rejected takeoff. They then attempted to report said rto but it occurred as the 777 was reading back their takeoff clearance. The controller should have noticed the two simultaneous transmissions. Neither plane would have been able to tell their tx was blocked.
Bottom line the controller issued the 777 takeoff without confirming the e190 was clear of the runway.
@@unpopularopinion8608 That explanation makes a lot of sense, thanks!
Another excellent breakdown. Keep up the great work!
This one put me over the edge on this conclusion: the tech that runs air traffic radio needs to be replaced with a version that allows everyone broadcasting at once to be heard.
There are cues that transmission was stepped on and the E190 pilot should have repeated the call when they didn't get acknowledged by ATC. That said I'm not saying the system can't be improved.
@@JamesF0790 doesn’t matter. A system that relies on noticing something subtle like that is idiotic. The entire possibility of being “stepped on” needs to be abolished completely. It should sound like a conference call if multiple people start talking at once.
@@MegaBrokenstar It's not idiotic, it just requires mic discipline and to pay attention. The alternative is to upgrade EVERY SINGLE RADIO at once. Every single tower, every single plane, all of them at the same time around the whole world. And you won't get much benefit from it because instead of getting the transmission stepped on it'll just turn into a jumble of voices.
Like discord servers? Oh cmon 😅
Awesome content! Keep making these videos
I think you mean a “ departure clearance “ is not the same as a “ takeoff clearance “. A takeoff clx is just that…clearance to takeoff. 😎👍
This is a complicated situation but one question is:
why did one automatic system say the plane was airborne when it was definitely still on the ground??
He explained it in the video but both planes automated systems said the planes were in the air. The one system told the other they were in the air from the planes own signals. The other system thought okay they are In the air. By the time it realised they wasn't and created a conflict it was all over. The whole thing lasted less than a minute
Shouldn't a pilot reporting a rejected takeoff require an acknowledgement from ATC? And if not acknowledged, repeat until it is?
The pilot of the smaller jet was in error, by not repeating on no reply from ATC. If he had done so, then probably the 777's pilot would also be aware. And if ATC appears to be not responding at all, it seems sensible to me to take initiative and clear the runway in a safe manner, just by looking around and finding a spot to park safely. Since he could hear that the 777 was in the process of being cleared for take-off. Also, the 777 pilot should hold until he visually clears the runway, if the weather allows for that.
Workload? Well, if you just stopped after an aborted take-off, first thing to do is inform ATC. What could be more important than asking for confirmation, at that point?
Question- when a flight is cleared for takeoff, besides identifying the plane he’s talking to, does the ATC repeat which runway they’re cleared to take off from?
@@OwnedByACatNamedC.C. In UK yes, and the wind as well: "Speedbird 406 cleared take off runway 06 right, surface wind 050 at 10".
Imagine TCAS going off on the runway. "Traffic, descend!" :-D
Lmao, was thinking the same
Strange that the TWR controller was sitting with his back to the runway he/she was controlling... The controller should always have good visibility on the runway(s) he/she is controlling. Nice simulation.
I am in awe of air traffic controllers. It must take a very special brain to be able to keep all that information separated and logical. I couldn't do it if it was the last job in the world.
At 6:03 you're unfortunately incorrect... At least for US atc. If the planes have divergent departure paths, atc can clear the next plane before the previous has rotated. I don't know what amount is required, but i think it 3k or 6k feet.
Something like this happened to a family friend in the 1980's. Just on a much smaller scale.
He was taking off from an uncontrolled airport called Nut Tree in California. He was flying a Boeing Stearman a 1930's era open cockpit, 2 seat trainer bi-plane. As the plane is a tail dragger it is not easy to see directly forward. When taxiing the pilot weaves back and forth to see where they are going, but on take off you just have to hope noting is in the way until you gather enough speed to fly the tail.
In this case there was a plane landing, and a Cessna 172 taking off ahead of him.
The friend watched the 172 start its takeoff run then he lined up, waited long enough for the Cessna to take off then added power.
But the Cessna had rejected its takeoff and stopped on the runway. Our friend didn't see this until the tail started to fly but by then it was way to late. The propeller of the Stearman cut the Cessna's fuel tank open and a fire broke out at once.
No one was killed but it was a pretty scary crash.
Using the same frequency to communicate with multiple planes sounds like a really dangerous design.
Not really. there was a lot that went wrong here and the transmission being stepped on was only a small part of it. If the E190 pilot had repeated the call after not getting acknowledgment it wouldn't matter for example
You said that the tower clearing the 777 for takeoff while the e190 was still rolling... Is routine and expected of him 6:50. NO IT'S NOT. It might be routine for him..but operationally he has to make sure it's taken off and minimum separation is met.
Great reconstruction video. Amen 🙏
When a takeoff is aborted, the crew should broadcast that information twice or more instead of its one transmission possibly being blocked by another transmission?
Thanks. Another really interesting / informative vid.
Airliners don't have brake pads as such, each brake works more like a multi-plate motorcycle clutch. They do get very hot in a rejected take off though and should be inspected before flying. These missing radio transmissions do seem to be a common occurrence and there should be some way to resolve this. The obvious way is to repeat if you get no reply.
That's interesting, didn't know that but makes sense given the force needed to slow a plane. Watched an A380 brake test simulating an overloaded plane with minimum brake condition. A fire started but the test was a success.
The tyres also have fusible plugs; hot brakes can cause a plug to blow out. Happened to me once on a VC10 after an overweight landing; a tyre plug shot out like a bullet. Luckily the fire crew had all the pax well away from the mainwheel area.
It never ceases to amaze me that aviation continues to rely on awful, primitive radio technology from half a century or more ago.
I realise it's an exceptionally difficult transition to make, but nobody seems to even consider or discuss the role of radio technology when looking into preventative measures for these incidents.
There are indeed digital radio modes that can be used these days to pass messages and clearances between aircraft and ATC. But VHF AM voice communication has been the standard for about a century and is usually pretty reliable. One thing that has changed is that the early VHF radios were rarely transmitting on exactly the same frequency due to small errors in the transmitter. The whole reason why AM was chosen rather than FM is that if two AM radios transmit at the same time, then if they are on slightly different frequencies any receiving station will hear a distinctive whistle or beat note making it obvious that two stations were transmitting at the same time. FM receivers on the other hand will exhibit a "capture effect" and if two stations are transmitting on nearly the same frequency you will only hear the stronger station, which i why AM is better for this purpose. These days aircraft radios are far more accurate and all will transmit pretty much on the exact frequency selected, so you no longer get a beat tone and it is not always obvious that there is a second transmission. Increased accuracy has reduced safety in other areas as well - it used to be the case that even if two aircraft were flying toward each other at the same altitude along the same route, they would be unlikely to collide because they were unlikely to be exactly on course due to navigation errors. Nowadays with improved navigation equipment, navigation errors are likely to be meters rather than miles off course, making collisions more likely (until TCAS came along).
Well, the military still use radio. Number 1 military in the world.
There is a crucial lesson here that you missed: the radio systems of the planes are obsolete. The half-duplex communication of these radios was absolutely unavoidable in the 1930s when they were first installed, but full-duplex communication is now usual in almost every application except this one. When was the last time that you didn't hear something on the phone, cellular or otherwise, because you were talking at that time? We now even have conference calls with dozens of participants and with no problems like this one. In any voice communication system designed less than 30 ago the possibility of more than one person talking at the same time is handled nicely, and if it becomes necessary, alarms can be fitted to signal lost messages due to congestion. When the radio systems of planes were first designed, digital communications did not even exist in science fiction. Now almost no communications in the world are non-digital, except AM radio, FM radio, and plane communications.
There are LTE 4G radios like the Icom IP501M. It would require probably some kind of safety enhancement for use in an aeronautic environment, but nothing undoable.
I hope the ATC controller didn’t face too much backlash. He was probably used as a scapegoat to a degree but I can’t see any real mistakes he made
Excess automation, or insufficient automation, depending on how you look at it - a normal ground radar would have shown both planes in the runway.
Controllers should be relying on some kind of positive confirmation on take offs, other than looking through the windows and other colleagues' armpits. What if the visibility is poor? How can either a controller or following plane pilots be sure the runway is clear? We've seen how many important radio transmissions have been lost due to interference in other episodes. Aviation industry is stuck in Tesla's and Marconi's time. Of course, simplex radio must be there for redundancy as a simpler and a bit more reliable alternative, but for security's sake new protocols and communication technologies must be developed and deployed at last.
In low vis, the seperation is much greater.
Thankfully all survived in incident
Important distinction: ‘departure clearance’ instructions after take-off, often given before a ‘take-off clearance’ which is ‘cleared for take-off’.
More than one aircraft can be on the active runway for departure at a time, intersection departures. We call this ‘racking and stacking’.
In Tenerife low-visibility prevented line-of-sight confirmation of aircraft position, and language difficulties also caused problems. None of these things were factors in this case.
Fortunately the 777 has huge stopping power.
I think a key take-away from the video is that PILOTS are the last barrier to accidents happening, not controllers.
I like that you have the video end with the landing as it should have been for the flight in question. So even if there was a crash, the video ends with things as they should have been.
A mini Tenerife in Toronto is a horrifying thought. Fortunately you had a few factors both incidents did not share: Tenerife had thick fog roll with no ground positioning system, a skeleton crew on that weekend and a senior Dutch airline pilot on their tarmac with the patience of a tea kettle.
Mentour has a great video about it, with a bit more details about it, although everything is mostly covered here. Very complicated incident, all these systems in place but this situation couldn't be caught.
Fantastic graphics and presentation.
Very interesting. Initially I did thing ATC error, but when you went through the detail it seems to me like there was really no-one at fault. If there had been a collision then ATC would probably have got the blame but if your screen says a plane (that is on the ground) is in the air, (worse) you don't recieve a critical transmission and you can't see the runway/that part of the runway nor are you expecting trouble what are you supposed to think. I'm surprised the 777 managed to stop. Still, at least this video had a happy ending...except (perhaps) for the bird!
imho the one at fault is making someone responsible for two runways while he can only see one of them.
Probably meaning the airport itself is at fault.
Shouldn't the E190 expect an acknowledgment?
Excellent video. Thanks.
If shaving off 30 seconds is so critical, then it needs to be compensated for by putting an extra set of eyes, or two, in the tower to help deal with the additional workload. This shouldn't represent a huge cost when compared to the value of the machinery and lives in motion.
Oh I love your videos! This could have been Tenerife all over again!!!
It's the weirdest to hear that in 2020 we still have archaic radio comms like this and also that a B777 wouldn't have a sensor to indicate obstacles on a runway.
One of the rules in communication theory is that if a channel is overloaded, NO useful data goes through.
Can we just say the layers of systems that are in place can be better in this case?
So when skynet becomes aware,we still have a chance.
Next please make a video on china airlines 006.My dad's friend's father was onboard that flight.
i may have missed it, but did the E190 declare an RTO?
yes, but it was blocked by the 777 read back of the clearance.
Imagine if visibility was lower, like for example Tenerife or Linate
Tenerife 2.0, then.
Thanks for the content, usually the Canadian controllers wait until the nose wheel lifts off that way they would know the V1 is way back no matter what.
Maybe a stupid question, but is there a way where radio messages sent to control at the same time could be buffered, and then played sequentially, rather than cutting off the second message?
No. That's not how radio works, it's a signal and frequency. Microwave signal. In order add buffer you need the receiver to be slow as well. But here's the logic, if two signals colliding each other that would interfere the clear signals and would cause the ATC to hear distorted noise.
7:33 Seems this could have been completely avoided if one or both pilots remembered to follow the basic rule of radio communication on a shared frequency: Listen before you key (the microphone).
Even if everyone listens first, sometimes two people key their mic at the same... blocked. Even worse if they also end their transmission simultaneously, because only a third party hearing the garbled transmission knows that it happened. Usually whomever unkeys first hears the end of the other's tx so they know they were blocked.
@@unpopularopinion8608 Yes, I understand that.
@@sct913 I think in this case the e190 was focused on the rto and didn't realize they hadn't reported it until they heard the tower launch the 777.
The ASMGS?
In regards to safety issues - it seems that the audio quality of ATC transmissions, or at least what can be heard on a video about aviation or even a live plane spotting broadcast, is rarely of clear audio quality. I have to read subtitles when available to understand clearly what’s being said. Also, as it relates to your presentation, I’m surprised that it’s still possible for a pilot’s radio communications to be stepped on. Is this being evaluated for improvement in any way? I understand that confirmation read-backs of communications are crucial, but it seems quite risky to rely on pilots & ATC’s to never forget to confirm a message.
Also, it seems that the standard ATC expressions “takeoff clearance” & “cleared for takeoff” - related, yet meaning different actions, could use a change to eliminate confusion for pilots. They might also misinterpret these if they experience poor audio quality. Also, I have a question: besides ATC identifying the plane they are communicating with, do they also repeat the runway again that a pilot is cleared to takeoff from? That way, a pilot in a similar situation to this video might pay closer attention to ATC communications with other pilots, if they hear their runway being called out.
I was wondering why the E190 pilot, not having received a confirmation for the rejected takeoff transmission, did not try again. Or was the timing too short for that?
I mean a lot of little things went wrong
1. The 777 needed to visual verify that the plane was airborne before it took off (if able)
2. If the pilot got no acknowledgement from ATC on an abort, they should've attempted their transmission again at least 15 seconds after the failed call
3. There should be a fallback system that let's other planes know that they're still on the ground. That system should not be hard-coded, and should change back to on ground if it detects any braking or the speed goes back under the threshold
Great that you cover lesser known and non tragic events. Obviously the pilot monitoring on the Embraer should have followed up the lack of acknowledgement of his rejected take off call out but this there should be some way to eliminate simultaneous transmissions on aircraft frequencies. These radio calls can certainly become mundane but they are extremely critical. Maybe tie the A-SMGCS to the WoW switch. Also when you bring any vision reducing factor into this scenario this system looks to be set up for an eventual disaster. Rare and unlikely? Sure. But is that good enough? Burt Rutan suggested a synthetic-aperture radar image projected onto the windscreen. Theoretically the pilot flies the same in zero visibility as VFR. Could this be possible?
i love these almost-crash investigations. much less well known but equally as interesting
ATC gave 2 aircraft take-off clearances based on a flawed systems design, without confirming visually ATC then directed their attention to another runway which is around 4 kms away.
Toronto is notorious for 1 controller trying to do everything. I’ve had the same controller giving IFR clearance, taxi clearance and tower clearance all at the same time. This is an accident waiting to happen, NAV Canada is not adequately staffing YYZ and is not seeing the bigger issue when 1 controller tries to do everything.
Almost hit every opening in the swiss cheese model... yikes
In UK a take-off clearance is a clearance to take off. What this video describes as a 'take off clearance' is an 'airways clearance' in UK.
But what happened after this?, what corrective actions/directives implemented?
None. Both aircraft crew would probably filed a report to their airline about this incident and the airline will investigate it and with conclusions they will probably increase the pilots training on communication and also give a recommendation to the involved airport to improve their equipment even more.
Love the channel. Request. When you mention a runway “270L“ could you show a map of the airport and show which runway and the direction the particular plane is flying in Ta over and out.
Great video.
Torontonian here, and all I can say is holy shit, and glad this didn’t play out tragically.
As soon as you said they talked over each other, I thought Tenerife. That was too similar, despite it being 50+ years later. If it hadn’t been clear, this would have been *almost* the same accident.
So what changes were implemented to avoid such a situation from occurring again?
*Lesson learned* for me, personally as a passenger: avoid busy airports if you possibly can.
I wonder, can't they have some traffic lights installed at the start of each runway? Linked to the actual ground radar, not some other AI system.
So if the groundradar still detects the plane taking off, the lights say 'stop' for the next plane waiting to take off.
Of course such a system should be used as a final check after receiving the actual take off clearance from ATC.
Was there something wrong with the ERJ model or was that just me not seeing things correctly? I know the wings sit quite low on the jet but the wings in some shorts looked really bent up
Thank goodness - I thought of Tenerife too!
Seems like ADSB should have shown two planes on the runway, but I'm pretty ignorant of that system...
It's great you cover near misses too because just as much can be learned at a far lower cost.....
It just wasn't another Tenerife because the Canadian plane aborted takeoff as it could see the E-190 still in the same runway, as there was no thick fog or thick mist covering the runways like in Tenerife.
It's Canada, so...
It's obviously settings used by the automated ground safety systems. By the way, if there was only one runway why was the controller not in the seat facing that runway instead of to the side and rear of the control tower?
6:10 you said for the uninitiated a takeoff clearance is not permission to takeoff. I’m a pilot and I guess every time the tower tells me cleared for takeoff I shouldn’t have taken off then 💁🏻♂️ so maybe you meant IFR departure clearance which is not a takeoff clearance
Ah, once again the antiquated AM radio tech that airplanes use, leads to a potential disaster
The preliminary reaction was to blame the ATC, but it was actually the system yielding false information. It is a good example of how jumping to conclusions without all the facts is a mistake.
I think the major causes were the unintended consequence of the two ground radar systems which were not designed to interact with each other, and the 190 pilot failing to repeat his departure information when he might have known that there had been a cross-transmition.
The seating position of the controller, having to stand up to look at the other runway, might also have been significant and maybe that needs to be considered in a tower reconfiguration.
yeah, so much money spend on building a special tower for the ATC so they can see what's going on and then put the controller on the opposite side so he can't see what's going on...